* arch/sh/kernel/head.S
*
* Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
+ * Copyright (C) 2010 Matt Fleming
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/thread_info.h>
+#include <asm/mmu.h>
+#include <cpu/mmu_context.h>
#ifdef CONFIG_CPU_SH4A
#define SYNCO() synco
.long 1 /* LOADER_TYPE */
.long 0x00000000 /* INITRD_START */
.long 0x00000000 /* INITRD_SIZE */
-#if defined(CONFIG_32BIT) && defined(CONFIG_PMB_FIXED)
+#ifdef CONFIG_32BIT
.long 0x53453f00 + 32 /* "SE?" = 32 bit */
#else
.long 0x53453f00 + 29 /* "SE?" = 29 bit */
ldc r0, r7_bank ! ... and initial thread_info
#endif
+#ifdef CONFIG_PMB
+/*
+ * Reconfigure the initial PMB mappings setup by the hardware.
+ *
+ * When we boot in 32-bit MMU mode there are 2 PMB entries already
+ * setup for us.
+ *
+ * Entry VPN PPN V SZ C UB WT
+ * ---------------------------------------------------------------
+ * 0 0x80000000 0x00000000 1 512MB 1 0 1
+ * 1 0xA0000000 0x00000000 1 512MB 0 0 0
+ *
+ * But we reprogram them here because we want complete control over
+ * our address space and the initial mappings may not map PAGE_OFFSET
+ * to __MEMORY_START (or even map all of our RAM).
+ *
+ * Once we've setup cached and uncached mappings we clear the rest of the
+ * PMB entries. This clearing also deals with the fact that PMB entries
+ * can persist across reboots. The PMB could have been left in any state
+ * when the reboot occurred, so to be safe we clear all entries and start
+ * with with a clean slate.
+ *
+ * The uncached mapping is constructed using the smallest possible
+ * mapping with a single unbufferable page. Only the kernel text needs to
+ * be covered via the uncached mapping so that certain functions can be
+ * run uncached.
+ *
+ * Drivers and the like that have previously abused the 1:1 identity
+ * mapping are unsupported in 32-bit mode and must specify their caching
+ * preference when page tables are constructed.
+ *
+ * This frees up the P2 space for more nefarious purposes.
+ *
+ * Register utilization is as follows:
+ *
+ * r0 = PMB_DATA data field
+ * r1 = PMB_DATA address field
+ * r2 = PMB_ADDR data field
+ * r3 = PMB_ADDR address field
+ * r4 = PMB_E_SHIFT
+ * r5 = remaining amount of RAM to map
+ * r6 = PMB mapping size we're trying to use
+ * r7 = cached_to_uncached
+ * r8 = scratch register
+ * r9 = scratch register
+ * r10 = number of PMB entries we've setup
+ * r11 = scratch register
+ */
+
+ mov.l .LMMUCR, r1 /* Flush the TLB */
+ mov.l @r1, r0
+ or #MMUCR_TI, r0
+ mov.l r0, @r1
+
+ mov.l .LMEMORY_SIZE, r5
+
+ mov #PMB_E_SHIFT, r0
+ mov #0x1, r4
+ shld r0, r4
+
+ mov.l .LFIRST_DATA_ENTRY, r0
+ mov.l .LPMB_DATA, r1
+ mov.l .LFIRST_ADDR_ENTRY, r2
+ mov.l .LPMB_ADDR, r3
+
+ /*
+ * First we need to walk the PMB and figure out if there are any
+ * existing mappings that match the initial mappings VPN/PPN.
+ * If these have already been established by the bootloader, we
+ * don't bother setting up new entries here, and let the late PMB
+ * initialization take care of things instead.
+ *
+ * Note that we may need to coalesce and merge entries in order
+ * to reclaim more available PMB slots, which is much more than
+ * we want to do at this early stage.
+ */
+ mov #0, r10
+ mov #NR_PMB_ENTRIES, r9
+
+ mov r1, r7 /* temporary PMB_DATA iter */
+
+.Lvalidate_existing_mappings:
+
+ mov.l .LPMB_DATA_MASK, r11
+ mov.l @r7, r8
+ and r11, r8
+ cmp/eq r0, r8 /* Check for valid __MEMORY_START mappings */
+ bt .Lpmb_done
+
+ add #1, r10 /* Increment the loop counter */
+ cmp/eq r9, r10
+ bf/s .Lvalidate_existing_mappings
+ add r4, r7 /* Increment to the next PMB_DATA entry */
+
+ /*
+ * If we've fallen through, continue with setting up the initial
+ * mappings.
+ */
+
+ mov r5, r7 /* cached_to_uncached */
+ mov #0, r10
+
+#ifdef CONFIG_UNCACHED_MAPPING
+ /*
+ * Uncached mapping
+ */
+ mov #(PMB_SZ_16M >> 2), r9
+ shll2 r9
+
+ mov #(PMB_UB >> 8), r8
+ shll8 r8
+
+ or r0, r8
+ or r9, r8
+ mov.l r8, @r1
+ mov r2, r8
+ add r7, r8
+ mov.l r8, @r3
+
+ add r4, r1
+ add r4, r3
+ add #1, r10
+#endif
+
+/*
+ * Iterate over all of the available sizes from largest to
+ * smallest for constructing the cached mapping.
+ */
+#define __PMB_ITER_BY_SIZE(size) \
+.L##size: \
+ mov #(size >> 4), r6; \
+ shll16 r6; \
+ shll8 r6; \
+ \
+ cmp/hi r5, r6; \
+ bt 9999f; \
+ \
+ mov #(PMB_SZ_##size##M >> 2), r9; \
+ shll2 r9; \
+ \
+ /* \
+ * Cached mapping \
+ */ \
+ mov #PMB_C, r8; \
+ or r0, r8; \
+ or r9, r8; \
+ mov.l r8, @r1; \
+ mov.l r2, @r3; \
+ \
+ /* Increment to the next PMB_DATA entry */ \
+ add r4, r1; \
+ /* Increment to the next PMB_ADDR entry */ \
+ add r4, r3; \
+ /* Increment number of PMB entries */ \
+ add #1, r10; \
+ \
+ sub r6, r5; \
+ add r6, r0; \
+ add r6, r2; \
+ \
+ bra .L##size; \
+9999:
+
+ __PMB_ITER_BY_SIZE(512)
+ __PMB_ITER_BY_SIZE(128)
+ __PMB_ITER_BY_SIZE(64)
+ __PMB_ITER_BY_SIZE(16)
+
+#ifdef CONFIG_UNCACHED_MAPPING
+ /*
+ * Now that we can access it, update cached_to_uncached and
+ * uncached_size.
+ */
+ mov.l .Lcached_to_uncached, r0
+ mov.l r7, @r0
+
+ mov.l .Luncached_size, r0
+ mov #1, r7
+ shll16 r7
+ shll8 r7
+ mov.l r7, @r0
+#endif
+
+ /*
+ * Clear the remaining PMB entries.
+ *
+ * r3 = entry to begin clearing from
+ * r10 = number of entries we've setup so far
+ */
+ mov #0, r1
+ mov #NR_PMB_ENTRIES, r0
+
+.Lagain:
+ mov.l r1, @r3 /* Clear PMB_ADDR entry */
+ add #1, r10 /* Increment the loop counter */
+ cmp/eq r0, r10
+ bf/s .Lagain
+ add r4, r3 /* Increment to the next PMB_ADDR entry */
+
+ mov.l 6f, r0
+ icbi @r0
+
+.Lpmb_done:
+#endif /* CONFIG_PMB */
+
#ifndef CONFIG_SH_NO_BSS_INIT
/*
* Don't clear BSS if running on slow platforms such as an RTL simulation,
3: .long __bss_start
4: .long _end
5: .long start_kernel
-6: .long sh_cpu_init
+6: .long cpu_init
7: .long init_thread_union
+
+#ifdef CONFIG_PMB
+.LPMB_ADDR: .long PMB_ADDR
+.LPMB_DATA: .long PMB_DATA
+.LPMB_DATA_MASK: .long PMB_PFN_MASK | PMB_V
+.LFIRST_ADDR_ENTRY: .long PAGE_OFFSET | PMB_V
+.LFIRST_DATA_ENTRY: .long __MEMORY_START | PMB_V
+.LMMUCR: .long MMUCR
+.LMEMORY_SIZE: .long __MEMORY_SIZE
+#ifdef CONFIG_UNCACHED_MAPPING
+.Lcached_to_uncached: .long cached_to_uncached
+.Luncached_size: .long uncached_size
+#endif
+#endif
git.openpandora.org / pandora-kernel.git / blobdiff